You must stop _____. My father is sleeping. [ ]
A. talk
B. talking
C. to talk
D. talks
答案:B
直流电动机中影响换向的因素应该是()
A.电抗与电枢反应
B.电抗与物理化学
C.电枢反应与机械
D.前面三个答案都正确
若客户忘记电话银行密码怎么办?